Update: Influenza Activity -- United States

Surveillance data indicate a continued decline of national
influenza morbidity and mortality. For the week ending March 30,
1985, no state reported widespread outbreaks of influenza-like
illness, and one state (Virginia) reported regional outbreaks. Of
total deaths reported by 121 cities for the same week, 5.7% were
associated with pneumonia or influenza, compared with the 7.3% of
total deaths that were associated with pneumonia or influenza for
the
peak weeks of the season.

Influenza type B viruses have been isolated from students and
teachers during two outbreaks in Hawaiian elementary schools. The
first outbreak began on March 7 and continued for approximately a
week, resulting in an increase in the school absentee rate from 5%
to
15%-20%. Influenza type B virus was isolated from four students
who
were ill during this outbreak. The second outbreak occurred among
a
group of children from four classrooms of an elementary school that
had toured the island of Hawaii from March 13 through March 15 in
two
large motor buses. One child had left the tour on March 15 with a
high fever and sore throat. Throat cultures from the ill student
were
negative for bacteria, and viral testing was not attempted. Soon
after they returned home, an outbreak of influenza-like illness
began
in the two classes that had traveled on the bus with the ill
student;
classroom absentee rates exceeded 50%. Less illness occurred in
the
two classes that had traveled on the other bus, but their absentee
rates were also above normal. Influenza type B was isolated from
two
students and a teacher who traveled with the ill student. These
are
the first reports of documented outbreaks of type B influenza in
the
United States this season.
Reported by C Ibara, G Kunimoto, S Naka, G Kobayashi, A Liang, MD,
State Epidemiologist, Hawaii Dept of Health; Participating
physicians
of the American Academy of Family Physicians; State and Territorial
Epidemiologists; State Laboratory Directors; Other collaborating
laboratories; Statistical Svcs Br, Div of Surveillance and
Epidemiologic Studies, Div of Field Svcs, Epidemiology Program
Office,
WHO Collaborating Center for Influenza, Influenza Br, Div of Viral
Diseases, Center for Infectious Diseases, CDC.

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